JB/T 9741-1999 This standard is a revision of NJ 26-86 "Technical Conditions for Valve Lifters". During the revision, only editorial changes were made according to relevant regulations, and the main technical content has not changed. This standard specifies the technical requirements, inspection methods, inspection rules and marking, packaging, transportation and storage of valve lifters for internal combustion engines. This standard applies to valve lifters for reciprocating internal combustion engines with a cylinder diameter less than or equal to 200mm. It is applicable to mushroom-shaped or cylindrical valve lifters for tractors, combine harvesters, automobiles, construction machinery, stationary and small marine diesel engines. This standard was first issued in 1964, revised for the first time in 1975, and revised for the second time in 1986. JB/T 9741-1999 Technical Conditions for Valve Lifters for Internal Combustion Engines JB/T9741-1999 Standard download decompression password: www.bzxz.net

ICS2-00
Machinery Industry Standard of the People's Republic of China
JBT9741-1999
Internal combustion engines
Technical Specifications
Valve Tappets
Internal combustion enginesTappcts Specifications1999-09-17 Issued
State Machinery Industry Bureau
2000-01-01 Implementation
JB/ 9741-1999
This standard is a revision of NJ26-86 (Technical conditions for valve tappets). Only the original standard was edited and revised, and the main technical content remained unchanged.
This standard replaces NJ266 from the month of implementation. This standard is proposed and managed by the National Technical Committee for Standardization of Internal Combustion Engines. The initiator of this standard: Shanghai Internal Combustion Engine Research Institute. The main initiator of this standard: Che Shao Nang.
4 The standard was first issued in 1964, first accepted in 1975, and revised for the second time in 1986. Scope
Mechanical Industry Standards of the People's Republic of China
Internal combustion engines, valve tappets, technical conditions
[ntermal eumbustiun engines-Iappets-spcrifientionsJE/T 974[—[999
This standard specifies the technical requirements, inspection methods, inspection rules and marking, packaging, transportation and operation of internal combustion engines: This standard applies to valves for reciprocating internal combustion engines with a cylinder diameter of less than or equal to 2n0mm (referred to as valve stems 1). It is also used for tractors, combined harvesters, automobiles, long-distance engines, stationary and small boat engines. Note 2 Reference standards
The provisions contained in the underlined standards become the provisions of this standard through reference in this standard. This standard is published for: The versions shown are all valid, and all standards will be subscribed. The parties using this standard should explore the possibility of using the latest versions of the following standards: GE:T 699—1988
GB:T1184—[996
GB.T1348—1988
GBT[800.3—1998
GB,T2828—1987
GB/T3077—1988
3 Technical requirements
Technical conditions for high-quality carbon and steel
Shape and position tolerances without reference values
Spherical iron parts
Limits and fits, Part 3: Standard tolerances and basic deviations numerical tables for batch inspection, sampling numbers and oil sample tables (applicable to continuous batch inspection) 3.1 Valve lifters shall be manufactured in accordance with product drawings and technical documents approved through prescribed procedures. 3.2 Materials Www.bzxZ.net
Valve lifters shall be made of 20Cr, 20Mn2H20, 50Mn2Steel specified in GB/T3077-1988; 23, 45mm2 steel specified in GB/T699-[98B; QT600-3 specified in GB/T1348-1988; or cold cast steel specified in product drawings. 3.3 Heat treatment and hardness
3.3.1 Valve lifters made of 20Cr, 20Mn2H20, 20Mn2Steel shall have a carbon content of 0.04% or a carbon content of 0.04%. The depth of the cold layer is 0.8~1.5mm, the hardness is 56~63HRC,
1.3.2/45, the valve support made of 50Mn2 steel should be tempered, and the hardness of 45 steel is not less than 55HRC; the hardness of 5Mn2 steel is: 7-.S4HRC-
3.3.3 The valve tappet made of QT600-3 is tempered, and the hardness is 53~60HRC. 3.3.4 The working end face of the valve stem made by cast casting can be cold cast or tempered after cold quenching. The depth of the cold layer is 2-m! The depth of the cold layer is 7-5mm. The hardness of the cast cold quenching layer is not less than 53HRC: the hardness of the reverse hard layer is not less than 56HRC, and the hardness of the valve stem is not less than 38HRC or the required value specified in the product drawing. 3.3.5 For valves with screw holes, the inner surface of the holes should be protected from magnetism and fire. Approved by the State Administration of Machinery Industry on September 17, 1999, 2000-0[-01 Inquiry
3.4 ​​Microstructure of Kumquat
JE/T97411999
3.4.1 After carbon or hydrogen annealing, the surface of latent carbon steel becomes fine needle-like martensite, and continuous network carbon addition is not allowed. The core is low-carbon martensite and titanium.
3.4.245 and 50Mn2 steels become fire-resistant martensite and less martensite after tempering. 3.4.3 The matrix composition of QT600-3. The content of martensite should be not less than 75%, and fine needle-like tempered martensite should be present after tempering. 3.4.4 The chilled cast iron chilled layer should be uniformly distributed fine eutectic carbides and ferrites. After annealing and tempering, the annealed layer should be carbides and tempered martensitic.
3. The valve tappet surface is not allowed to have defects such as damage, potting, pores, looseness, flow and non-metallic inclusions. 3.6 The dimensional tolerance of the valve tappet surface should not be less than T? specified in GB1800.31998. 3.7 The surface roughness R of the main valve tappet surface shall not be less than the following values:) Working surface 0.4 μm:
b) Column surface 0.63 μm:
c) Ball socket surface 1.6 μm:
3.8 The shape and position tolerances of the main parts of the valve tappet: a) The shape tolerance of the surface shall not be less than Grade 6 specified in Table B2 of GB 184-1996; b) The half surface tolerance of the working end surface (only 3.9 The working end face of the valve tappet shall be treated with surface treatment or other surface treatment. 3.10 During the warranty period of the internal combustion engine, if the valve tappet is damaged due to poor manufacturing, the manufacturer shall replace it free of charge. 4 Acceptance rules
4.1 Each valve shall be inspected and qualified by the inspection department of the manufacturer before it can leave the factory. 4.2 When the ordering unit samples the required quantity of products, it shall be carried out according to the single sampling plan and one-stage inspection level II specified in G228-1987, and the qualified quality level AQL value shall be 1.0. The sampling can also be carried out according to other sampling methods agreed upon by the supply and demand parties. Find packaging, marking and storage
5. The valve tappet must be cleaned, oil sealed and packaged. The validity period of the oil seal is not less than 12 months. 5.2 The packaged valve tappet should be placed in a cardboard box. The carton should be marked with: a) manufacturer name, factory logo and address; b) engine model, part name and part number; s) packaging date.
5.3. There should be waterproof paper in the packaging box, and it should be ensured that the parts will not be damaged during the belt transportation. The total weight of each box should not exceed 50kg-5.4. The packaging box and carton should be accompanied by a packing list signed by the manufacturer's inspector and the packer. The list should indicate the engine model, part name, required part number, number of trays, etc. tt||5.5 Each paper cone should be accompanied by a product certificate signed by the inspector. The certificate should indicate: manufacturer name, factory logo and address: 6 diesel engine model, part name, part number: c) Inspection date
5. Before packaging, please note:
a, name, factory logo and address: , diesel engine model and part name
c) Packing date, quantity:
d) Receiving unit name and address:
) "Handle with care", "Anti-swimming" and other signs: JB/T9741-1999
5, the valve is too thick and the packaging box has ventilation and color inside
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